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2021 ANNUAL GROUNDWATER MONITORING REPORT TEICHERT AGGREGATES AND GRANITE CONSTRUCTION VERNALIS AREA approximate depth of 250 feet beneath the Vernalis Central Phase 1 and 8 that appeared to divide the underlying aquifer into shallow and deep zones.This clay is most likely the Corcoran Clay Member of the Tulare Formation,which has been reported to extend beneath much of the San Joaquin Valley, including the present monitoring network area (Hotchkiss, 1972). Further,the investigation indicated that the direction of groundwater flow in the shallow zone was predominantly to the southeast. Since 1994,groundwater levels have been obtained from a total of sixteen wells(Figure 2).The Thoming irrigation well was destroyed in early 2013. Since 2006,water level measurements in the irrigation well 4S/6E-6A1 have been precluded by an obstruction at a depth of approximately 100 feet(bgs). From fall 2018 through 2020,water level measurements in the Koster irrigation well were precluded by instrumentation of the California Department of Water Resources that lodged in the well casing. From 2016 through 2020,water level measurements in the Rustan well were infrequent due to site access limitations. Until spring 2021,South Tracy#3 had an obstruction at approximately 271 ft bgs and was only accessible for water levels that were above the obstructed depth. Prior to 2019, port access at the Granite#3 well had been difficult and only a few measurements had been obtained since this well was incorporated into the network in 2006. During spring 2019,the pump was removed from Granite#3 and water levels were obtained through fall 2021 when the sounding port was sealed. In fall 2017,Granite #4 and Brown's New well were rehabilitated.After the rehabilitation,the sounding port at Granite#4 was obstructed at approximately 370 ft bgs (approximately 285 ft bgs starting in 2020) and was only accessible for water levels that were above the obstructed depth. In spring 2021,the obstruction was no longer present and since then, water level measurements have been successfully obtained.An airline was installed in the Brown's New well to obtain water levels, but it was destroyed by wildlife in spring 2018 making the well inaccessible for water level measurements.The airline was repaired,and pressure readings were obtained in 2019 and spring 2020. In summer 2020,the pump was temporarily removed, and a water level was obtained. By fall 2020,the pump was re-installed, however there was no longer an airline and no access to the well for water level measurements. In 2021,the well was accessible for water level measurements, however,the well has been pumping during most monitoring campaigns. In 2019,the Granite#5 production well was incorporated into the monitoring program. Pressure readings were obtained in its airline but due to a leak in the airline,the pressure readings are not representative and therefore were not converted to depth to water or water level elevations. In fall 2021,the pump was removed from the well and there was no access for a water level measurement. The groundwater quality network consists of 2 wells upgradient from the Vernalis plant(Hall and Faulkner domestic wells), 1 well onsite (South Tracy#3 production well),and 2 downgradient wells (Granite#5 and Brown's New production wells) (Figure 3).The monitoring network has experienced modifications over time. For example,the South Tracy#3 production well was added to the water quality network in 2004 in lieu of the Brown's New well,which became inoperable in 2001 (due to the removal of the pump).With Granite's commencement of mining activities,the Brown's New well was equipped with a pump again and was incorporated back into the monitoring program in 2009 as a replacement for the South Tracy#1 well. Further,from 2006 to spring 2018,the Granite#3 well LUHDORFF&SCALMANINI CONSULTING ENGINEERS 2